Josiah e



(No Model.)

J. E. WEST'SU C. O. WHIPPLE. PROGBSS 0F MANUPATURING ARTICLES 0F PLASTIC' MATERIAL.'

No. 508,494. Patented Nov. 14, 1893.

Unire STATES kPMs-:NT Frise.

JOSIAH E. WEST AND CARLOS O. WHIPPLE, OF ST. CLOUD, MINNESOTA;

ASSIGNORS TOA THE ST. CLOUD VULCANIZED FIBREWARE COMPANY,

OF SAME PLACE.

PROCESS OF MANUFACTURING ARTICLES OF PLASTIC` MATERIAL.

lSPECIFICATION forming part of Letters Patent No. 508,494, dated November 14, 1893.

' Application filed MaylQ, 1893; Serial No. 474,826. (No specimens.)

To all whom it may concern: f

Be it known that we, JOSIAH E. WEST and CARLOS O. WHIPPLE, citizens of the United States, residing at St. Cloud, in the county of Stearns and State of Minhesotaphave invented certain newand useful Improvements in Processes of `Manufacturing Articles of Plast1c Material, of -which'the following is a specification.

The primary object of our invention is to manufacture buckets or pails of paper pulp,

or similar fibrous material, having combined therewith a suitable binding agent; but, some parts or certain features of our improvements mayV also be employed in the manufacture of table tops, ornamental molding, electrical goods and various other'similar articles. i

We will show and describe our improvements as employed in the manufacture of paper pails, but we wish vit understood that by suitably modifying the process and apparatus, other kinds of articles may be made.

Hollow ware articles have heretofore been extensively made from paper. pulp by various processes, but generally by Whatis known as the wet process. There are very few instances in which hollow ware has been made in molds from granulated or powdered pulp,

but the latter way possesses many advantages, as the articles may be madehard and durable and capable of resisting the action of hot or cold water, acids and alkalies, by

simply combining-.with thepowdered pulpY suitable substances.

So far as the invention claimedin the present case is concernedQtheparticular kind of brous material and binding agent employed is not important, but inorder that our entire process may be fully understood,we would state that we preferably take ground wood pulp and mix it with chemical or sulphite f pulp, preferably in'a beating engine, but

Vthe ordinary quantity.

improved result; or, we may take ground wood pulp and mix it with say twenty-five per cent. of-lax tow, previously cooked or steamed in lime water. In the beating engine, we treat the mixed pulp with a rosin sizing,which may be such as ordinarily employed in the manufacture of paper, but we use more than In connection with the rosin, we preferablyV employ lime after it has been slaked and impregnated with oil, tallow, or other grease, and to this mixture, We add alum to set the sizing, and if it is desiredto color the mixture, We add a suitable pigment. When thoroughly mixed, we transfer the pulp to a wet machine, to form it into sheets, or transfer it to vais to drain. After being thoroughly dried, it is passed to a re; grinder, which granulates the pulp, great care being taken to prevent, as far as possible, the fiber from being powdered, and the resulting material 'is fluy or like wood wool, and has a gummy feeling. Preferably, while in the re-grinder, we add finely pulverized rosin as an additionalvbinder. The material in this condition is now ready for the first or what we call the warm press. As before stated, the selection of materials and the particular way of treatingthem does not form part of the invention herein claimed.` They are claimed inour application yforI patent, Serial No. 450,227, filed October '25.1224

Thesteps 'fmthe process above described may be slightly Varied. The mixing of the ground woodpulp and sulphiteor chemical Ipulp or iiax tow, or water-proof paper, can be eecte'd after the ingredients have'been dried and re-ground, by placing themin a revolving mixing machine, at which time the rosin and treated lime may be added, and the pig- `ment for coloring, if desired, may also be We form in the warm press, above 'mentioned, the body or side ot' the pail, but instead of making it round or circular, we forni the body fiat, or substantially so, and also form at the edges suitable bevels or tongues and grooves to make the seam or joint; or, We may form the edges in any suitable way so that they may match and when compressed will readily adhere to each other. This particular feature of our invention is claimed in another application filed by us May 12, 1893, and serially numbered 473,944. In the warm press, the pulp is pressed into sh ape, not innch pressure being required and that only for a short time. lf it is desired to add strengthening strips or pieces of metal, or other like material, we first partially fill the warm press with pulp and then put the hoop` sheet or strip in position and then put iii additional pulp and apply pressure. The bottom of the pail maybe formed in a similar press or warm die, or, as preferred, it may be formed by placing granulated material in the body blank and then compressing it into shape. After the body blank is formed into shape and allowed to cool, or immediately after it is taken from the warm press, it may be treated to a coating of rosin oil, or if a large amount of pulverized rosin has been mixed with the pulp, then the blanks may be treated With linseed oil. The amount of oil to be used may be Varied according to the grade of pail required, and for cheap packing pails, this treatment will not be required at all. By this treatment, the oil permeates the blank and assists in melting the rosin and binding the fibrous material together and making the pail water-proof. When water proofed paper or pulp has been used this treatment may be omitted. The pail blank thus formed and treated, may then be taken to a former and bent into shape and allowed to cool. It is then transferred to a hot press or mold, and

l pnt in place and the pail bottom is applied,

which may be done either by forming a circular or disk-shaped blank and uniting it with the body, or, as we prefer, granulated material is placed in the body blank and is compressed and united with the blank in the hot press. When the body blank is thus placed in the mold, and the `granulated material is arranged in the blank, the plunger is lowered, and by putting on great pressure,

say from two thousand to three thousandpounds to the square inch, the bottom is formed and united to the body and the pail is completely formed. The binding material and oil are melted and caused to impregnate all portions of the body and bottom, and a substantially homogeneous or seamless article isA produced. From the hot press, the pail is taken to a cold press, which is slightly smaller. than the hot press. It is there subjected to great pressure, and all blisters are removed from the surface of the pail," and it is hardened and given a smooth finish. It is also in this press given its final form. The

pail is then taken from the cold press and baked in an oven for say twenty-four hoursc; beginning at a temperature of about 15() Fahrenheit, and gradually increasing to a teniperature of about 250 Fahrenheit: T he pail may then be tinished by coating it with water-proof material, varnish, ebony finish, or other like material.

In the accompanying drawings, we have shown diagrammatically the different steps of the process.

Figure l shows the warm, fiat press where the body of the pail is formed. Fig. 2 is a view of the product of the warm, flat press. Fig. 3 is a view of the former in W'hichthe body blank is bent into shape. Fig/l is .a View of the product of the former. Fig. 5 is a view of the hot press. Fig. 6 is a View of the cold press, and Fig. 7, a view of the final product.

A indicates the outer or female member of the warm press, and B, the plunger. As will be observed, they are both chamber-ed and have entrance and exit pipes for the circulation of a heating agent. In order to form a beveled edge at each end of the blank, the bottom of the press is formed at a, with an inclined projection, and the plungeris formed at b, with a similar inclined rib or proJection. The material in a dry, granulated or filuy condition is placed in the press, and pressure is applied which will cause the particles to cohere, `and give to the mixture the de sired form. If it is desired to embed a st rip or sheet of metal or other stift' material in the ICO body of the blank, it may be done by first partially filling the mold A with granulated material, then placing a strip in position, then filling in more granulated material, and then applying pressure. The pail blank, such as indicated in Fig. 2, is next taken to a former, such as shown in Fig. 3, where it is bent into the shape indicated in Fig. 4. .It is then taken to ahot press C, which comprisesaplunger c, and an outer mold c', both of which are steam-heated. We then pour into the blank thus placed in the mold, a suitable quantity of the combined fibrous material and binding agent, as indicated in Fig. 5, and then the plunger is made to descend, which first c ompresses the granulated material, fiattens it to form the bottom, and causes it to firmly unite with the body blank, which is in a comparatively loose condition, and readily permits the granulated material forming the bottom to unite with it. Then, by applying heat and great pressure, the binding material is melted and caused to iinpregnate the pulpy or fibrous material, and the material is compressed and reduced to the desired thickness. The propress is slightly smaller than the hot press,in order that the material maybe firmly compacted. In the cold press, all blisters are re-` moved from the surface'of the'pail, and-it is hardened andl given a smooth finish. h

Weattach great importance to the use of a cold press, as'it enables us to remove the blisters and give the smooth iinish, just referred features of our invention are concerned, the;

materials employed may be varied'as may also the steps of the process and the apparatus employed.

We claim as our invention- 1. The process herein described, for theV manufacture of articles'from fibrous material, Which'consists in forming in a Warm press from groundv or powdered fibrous material, While dry and containing a binding agent, a blank for the article, then bending the blank into form, then subjecting the article to heat and pressure to melt the binding material and thereby combine it With the lber and sists-in forming a blank'foran article of iibrousmaterial, and a binding agent, then treating the blank thus formed with oil or similar material, then-cooling the article thus treated, and then subjecting it to heat and great pressure to melt and unite the binding material to the fibrous material and to give form to the article.

3. The process herein described for the manufacture ot' hollow Ware articles, which consists in forming from combined fibrous material and a binding agent,` While dry and in a luiy or granulated condition, a blank for the body of the article',lthen partially iiling theblank with the combined dried, granulated material and binding materiaL'and then by heat and pressure compressing and compacting this mixture to form the bottom of JosIAH E. WEST.`

oARLos o. WHIPPLE.

i/Vitnesses: y

L. T. TROUTMAN, J No.v BLATTNER. 

